GCSE›Edexcel GCSE Biology›Mind mapsThe Organism in the EnvironmentEdexcel GCSE Biology: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsLevelsOrganism = an individual living thingPopulation = one species in a habitatCommunity = populations of different speciesEcosystem = community + abiotic environmentAbiotic factorsNon-living physical or chemical factorsTemperature, light, water, pollutantsBiotic factorsLiving factors from other organismsCompetition for limited resourcesPredation = predator-prey interactionOrganismsecology basicsRelationshipsInterdependence: organisms rely on each otherParasitism: parasite benefits, host harmedMutualism: both organisms benefitSamplingQuadrat = square sampling framePlace quadrats randomly to avoid biasBelt transect: quadrats at intervals along a gradientEstimate = mean per quadrat × (total area ÷ quadrat area)Mean 5/m² over 500 m² → 2500Exam tipsPopulation is one species, community is manyRandom placement gives an unbiased sample